Copy Custom Field Values from Shipment Line to Invoice Line and Copy Custom Field Values from Purchase Order Header to Purchase Receipt Header

Hi I have 2 requirements,

1. Copy Custom Field Values from Shipment Line to Invoice Line (SOShipLine → ARTran)
2. Copy Custom Field Values from Purchase Order Header to Purchase Receipt Header (POOrder → POReceipt) 

How can I implement this? 

Is there a way I can use PXOverride and update the fields on invoice line creation and purchase receipt creation.

For example this is an implementation I did for copying field values from sales order header to shipment header screen.

public delegate void CreateShipmentDelegate(CreateShipmentArgs args);

        [PXOverride]
        public void CreateShipment(CreateShipmentArgs args, CreateShipmentDelegate baseMethod)
        {
            // Call the original method to ensure default behavior
            baseMethod(args);

            // Retrieve the current shipment and order
            SOShipment ship = Base.Document.Current;
            SOOrder order = args.Order;

            if (ship != null && order != null)
            {
                // Use the extension cache to access the custom fields
                SOShipmentExt shipExt = PXCache<SOShipment>.GetExtension<SOShipmentExt>(ship);
                SOOrderExt orderExt = PXCache<SOOrder>.GetExtension<SOOrderExt>(order);

                // Update custom fields in the shipment header
                shipExt.UsrCommission = orderExt.UsrCommission;
                shipExt.UsrCustomerPickUp = orderExt.UsrCustomerPickUp;
                shipExt.UsrDuty = orderExt.UsrDuty;
                shipExt.UsrFreight = orderExt.UsrFreight;
                shipExt.UsrInsurance = orderExt.UsrInsurance;
                shipExt.UsrQtyShow = orderExt.UsrQtyShow;
                shipExt.UsrQtyNote = orderExt.UsrQtyNote;
                shipExt.UsrShippingTermsINCOTERM = orderExt.UsrShippingTermsINCOTERM;
                shipExt.UsrCurrencyTerms = orderExt.UsrCurrencyTerms;

                // Update and save the shipment header
                Base.Document.Update(ship);
                Base.Save.Press();            
            }
        }

Thank you!